james s



(Speeimens.) 2 Sheets-Sheet 1.

J. S. MAUCOY.

METHOD OF MAKING A SMOOTH SURFACE 0N STONE, 850. No. 373,746.

Patented Nov. 22, 1887.

WITNESSES ATTORNEYS.

N. Pnms-nwwmw xm Wnhingiou. n c

(Speeimens. 2 Sheets-Sheet 2.

J. S. MAOOOY. METHOD OF MAKING A SMOOTH SURFACE ON STONE, 650. No. 373.746.

Patented Nov, 22, 1887.

- nV/l/ I/IZ! INVENTOR WITNESSES ATTORNEYS.

UNITED STATES PATENT Ostrich.

JAMES S. MAGCOY, OF BROOKLYN, NEW YORK.

METHOD OF MAKING A SMOOTH SURFACE ON STONE, 84G.

SPECIFICATION forming part of Letters Patent No. 373,746, dated l."'e-vemloer 22, 1887.

Application filed July 27, 1887. Serial No. 245,432. (Specimens) To all whom it may concern:

Be it known that I, James S. MuoCov, of the city of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Method of Making a Smooth Surface Upon Stone, Metal, of which the following is a full, clear, and exact descrip tion.

My invention consists of the method ofproducing a uniform or planed surface upon stone, metal, and other hard substances by a reciprocating as distinguished from a grinding action or motion, as hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar ietters of reference indicate corresponding parts in all the figures.

Figure l is a perspective View showing the manner of apply ing the tool to the work. Fig. 2 is a longitudinal sectional elevation of the pneumatic tool. Figs. 3 and 4 are reverse side elevations of the cylinder, the outer shell or jacket being removed. Fig. 5 is a side view of the striker, showing a valve-chamber of small diameter with induction and ednctiou passages leading into it. Fig. (his a sectional elevation taken on the lines :0 of Fig. 2, and Fig. 7 is a side view of the valve removed.

In carrying my invention into effect I employ a pneumatic tool, in which A represents the striker, and B the casing or cylinder composed of upper and lower parts screwed together, as shown in Figs. 1 and 2. Surrounding the cylinder is the jacket G, which, to gether with grooves and flattened surfaces formed in and upon the outer surface of the cylinder, (and hereinafter fully described,) forms the air ducts and passages through which the compressed air enters and exhausts from the cylinder.

The lower part or point. C, of the casing or cylinder carries the spindle D, that holds the cutter E, and upon the spindle within the point 0 is placed a coiled spring, F, the office of which is to return the spindle after each downstroke of the striker A.

The upper part of the cylinder B is formed with the air'iulet passage (1, Fig. at, and exhaust-passage Z), Figs. 2 and 3, and t is faced oit' at c, Fig. 4., andon the opposite side at dd (1. (Shown in Fig. 3.) In the flat surface 0 is formed the induction'port c, and the air-inlet passage c opens into said flat surface 0.

The exhaust-passage b opens out from the fiat surface (I, and in the flat surfaces 11 d are formed in the cylinder the exhaust-ports f f. From the flat surface 0 the cylinder is grooved, as shown at g, and on the opposite side, as shown at g. The groove 5/ leads to the port 72., (see full lines, Fig. 2, and dotted lines,Figs. 3 and 4,) while the groove 9 leads to the port h. From the flat surfaces d d are formed the grooves 2' i. The groove 6 leads to the portj, while the groove 2' leads to the port j. (Both ports shown in full lines, Fig. 2, and in dotted lines in Figs. 3 and 4.)

The striker A is formed with the transverse valve-chamber L, in which is placed the slide valve L, and the striker has formed init the passages 7c it, which reach through to the valvechamher, and these openings or passages coincide or stand in the same plane with the exhaust-ports f f respectively. The striker also has a passage, Z, formed in it, which also reaches through to the valve-chamber L, and this latter passage Zcoincides with or stands in the same plane with the inlet-port c, made in the cylinder B, and the striker also has the longitudinal passages m a formed in it, which reach,respectively, from the vaivechamber to the top and bottom of the striker, as shown in dotted lines in Fig. 2, through which the compressed air enters and exhausts from both ends of the cylinder for reciprocating the striker.

The valve L is circumferentially grooved, as shown at p 1), so that in its reciprocation caused by air entering the portsjj or it It it will open and close all the air-passages made in the striker.

The operation is as follows: The striker A being in its upper positiom'air is admitted to theinduction-portc, enters the passage formed by the flat surface a, and passes through the port 6 and port 71, moving the valve L to close passage in and to connect passages e Z 121., thus admitting air above the striker A, and at the same time the valve connects the passages n to allow exhaust from below the striker through the space formed by the fiat surfaces d d d and passage 1). Then the air through the passage g and port it moves valve L' to close the passage 7:, and to connect passages e Z a to admit air below the striker and to connect passages on, k, and f to open the exhaust from above the striker, and so on, alternately causing the striker to have a rapid reciproca tion. The air containedin the valve-chamber L at the ends'of the valve is exhausted with each movement of the valve through the ports j j alternately. The distance between the transverse plane of the port it and that of port h, together with the diameter of the valve-chamber L,dctermines the length of reciprocation of the striker -A, and these ports are arranged so that the cut-off by the valve L of the exhaust through the passages m a in the-striker is timed to maintain a cushion of air at both ends of the striker, so that there is no beating of the striker upon the cylinder and no beating of the striker upon the spindle D. The ports h j are arranged in the cylinder a distance from the spindle D (when seated) somewhat greater than that from the lower end of the striker to the valve-chamber L, so that the air cannot all exhaust from the cylinder, but a cushion of air will be always maintained between the striker and the spindle,which renders the blow of the striker percussive and effective without battering either the spindle or striker.

As it may be possible to carry out my method by other machines or modifications not yet made, without departing from the spirit of my invention, I do not wish to limit myself to 'the construction or arrangement shown, although I have so far been unable to obtain complete or full success by the constructions heretofore patented by myself or by others. The foregoing construction is in the main quite similar to that shown in my pre vious Patents, No. 323,053, of July 28, 1885, and No. 326,312, of September 15, 1885, yet there are important differencesdifferences which make the present construction a complete practical success, while that attained heretofore was only partial success at most.

After the purchase of and three years costly experiments with otherpatcnts most like the foregoing, together with my own inventing, I finally attained success mainly by securing an unprecedently high rate of speed (estimated as high as fifteen thousand strokes per minute) which could not be made by former machines, and which unexpectedly permits the use of thinner sharper-edged tools than could be used heretofore. These ends have been secured mainly by so changing the proportions and adjustments of the valve and parts as to give the striker a very short and an exceedingly rapid stroke, and by making the striker and its metallic cylinder with an appreciable difference in their diameters, thus forming an air-chamber around the striker, whereby an enormously rapid practically-continuous action is attained.

It was long ago discovered that to do good smooth work in turning and planing wood a high speed was necessary, and afterward it was discovered that to turn and plane metals a slow movement was required-that, for instance, the soft metal lead is cut very easily at a very slow speed, but at a high speed, best for wood, it will break the best-tempered steel tools. Likewise I have now discovered thata stroke-tool must have exceeding rapid strokes, when it takes a practically-continuous progressive movement and does a kind or quality of work not heretofore attained, producing a smoother finer-grained texture of finish than can otherwise be produced. The surface seems to be cut or pared off without breaking, chipping, or fracturing the surface to any depth, so that very little grinding is required to produce a perfect polish. Another peculiarity is that both alight out or kerf and a comparatively deep one may be made in succession by the same machine, or partly shallow and partly deep at the same time. Thus, with a curved-edged bit or chisel a bead, a groove,

or a molding may be cut in one operation, or

any variety of carving can be wrought out most expeditiously.

No one has ever before planed marble or metal with a stroke machine so far as I can learn. The successive strokes of the bit or tool are so very rapid that there is not time between them for the tool to rebound or quit contact withthe material; and, furthermore,

when each stroke does work, and thereby imparts mechanical energy, the tendency or ability to rebound has departed from the tool with that energy, and the tool thus makes a practically continuous progressive movement and planes the material, a result not accomplished by any machine heretofore patented or constructed.

W'hen, owing to the size of the tool, or otherwise, it is desired to economize weight in the valve L, I use a valve of a small diameter and form in the striker at either side ofthe valvechamber L the small grooves q q, to direct the compressed air to and from the valvechamber through the inlet and exhaust ports in the cylinder, and by these grooves the same short quick percussive blow may be maintained by making them of proper length relatively to the distance between the ports h j and hj.

In producing a uniform or planed surface the bit is kept in proper contact with the material by the hand of the workman or otherwise, as illustrated in Fig. 1, while the striker delivers upon the head of the bit-carrying spindle blows so rapid as to be practically continuous. In this way the bit never drops, but makes a constant out. A planed surface is thus produced by a cutting implement acted upon by a rapidly-reciprocating striker, a result not hitherto attained.

.Having thus described my invention, What I claim as new, and desire to secure by Letters Patent, is-

The method of making a smooth surface on stone, metal, or other hard substance by means of a reciprocating-stroke machine whose action is so rapid as to be practically continuous.

\Vitnesses:

H. A. WEST, J. M. BITTER.

JAMES s. M'ACCOY. 

